Objective Antibacterial properties of total extract and ethanol segments from stem of Evodia lepta（Spreng. ） Merr. in vivo and in vitro. Methods In vitro， minimum inhibitory concentration（MIC） was determined by using the serial 2-fold broth dilution methods. In vivo， a sepsis mouse model challenged with sublethal Staphylococcus aureus was established to evaluate the anti-infective effect of there samples. Results Except the MICs of the total exact for two Staphylococcus aureus strains ATCC29213， ATCC43300 were both 12.5 mg/ml（206.3 mg crude drug/ml）， the total exact had no significant inhibition on other pathogenic bacteria such as Escherichia coli， Pseudomonas aeruginosa， Klebsiella pneumoniae， and Enterococcus faecalis. In vivo， compared with the model group， the total extract of Evodia lepta（Spreng. ） Merr. significantly increased survival rate of the septic mice within 168 hours（P<0.01）. The survival rates were markedly higher in the segments（SYK20， 90）-treated groups than that in the model group（P<0.05； P<0.01）. The survival rate was highest in the SYK90， but it was slightly lower than the total exact. Conclusion Taken together， in vitro， the total exact from Evodia lepta（Spreng. ） Merr. significantly inhibits the growth of Staphylococcus aureus. In vivo， the total exact total extract and ethanol segments （SYK20， 90） significantly protects the sepsis mice challenged with sublethal Staphylococcus aureus.